Bugfix/#199 import performance

Bug fix

Summary

This MR provides a simple caching mechanism for the intermediate format created by the chain me:main => commons:add-IDs => tokenize:main within commons:get-page-fragment. Therefore a collection for temporary files is created $commons:tmp.

Compliance to “Definition of Done”

• Unit tests passed
• Code reviewed
• Product Owner accepts the User Story

Changelog

• I added a statement to the CHANGELOG.

Version number

• I bumped the version number in build.properties.

Readme and general docs

• I updated the README (if applicable) and kept the docs up to date.

Closes #199 (closed)

/cc Mathias Göbel, Frank Schneider, Michelle Weidling